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Thesis (M.S.)--University of North Carolina at Wilmington, 2005. / Includes bibliographical references (leaves: [69]-73)

Thesis (M.S.)--Eastern Illinois University, 2008. / Includes bibliographical references (leaves 46-49).

This thesis addresses the idea that colony formation effectively increases the size of a phytoplankter thereby reducing grazing losses by deterring ingestion by zooplankton. It was initially hypothesized that colonies of Dinobryon (Ochromonadales, Chrysophyceae) deter zooplankton grazers, and that their spring population declined either because of a drop in the mean colony size of the Dinobryon population or from an increase in the abundances of large zooplankton grazers capable of ingesting large colonies. From January to May 1983 a small dystrophic lake was sampled weekly at three discrete depths at two stations. In the samples collected from one station, two species of Dinobryon, D. cylindricum Imhof and D. diverqens Imhof, as well as all zooplankton species were enumerated and morphometric variables of Dinobryon colonies were measured. The results showed that, alone, each of the original hypotheses could not account for the population and colony size dynamics of the Dinobryon species present in the lake. A new hypothesis was generated from the results which suggested that Dinobryon colonies minimized grazing losses to small grazers because of increased size and to larger grazers by fragmentation upon capture. Subsequent evaluation of the assumptions of this new hypothesis, using both the original data and new data from the second station, added further support to the hypothesis. / Science, Faculty of / Botany, Department of / Graduate

Bibliography: leaves 309-329. This thesis attempts to contribute to the understanding of how turbulence affects phytoplankton in freshwater systems, focussing on the temporal and spatial scales in phytoplankton dynamics ranging from photochemistry in the surface mixed layer to a small-scale shear and growth to intra-seasonal changes in community composition in a lake subject to high disturbances.

Bibliography: leaves 309-329. / xvii, 329 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis attempts to contribute to the understanding of how turbulence affects phytoplankton in freshwater systems, focussing on the temporal and spatial scales in phytoplankton dynamics ranging from photochemistry in the surface mixed layer to a small-scale shear and growth to intra-seasonal changes in community composition in a lake subject to high disturbances. / Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, 2003

Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (leaves 155-163).

Mémoire (M. Sc. A.)-- Université du Québec à Chicoutimi, 1984. / Bibliographie: f. 77-81. Document électronique également accessible en format PDF. CaQCU

Thesis - University of Lund. / Added t.p. with thesis statement in Swedish inserted.

Following the U.S. Environmental Protection Agency’s specifications for pesticide registration tests, 12 experimental ponds were constructed in Blackstone, VA at VPI&SU Southern Piedmont Agricultural Experiment Station. Colonization and succession of the ponds’ phytoplankton communities were investigated during the first year after filling. Taxa richness and densities, biomass as chlorophyll a, and primary productivity (in situ oxygen method) were measured. In addition, water quality data were collected and analyzed. The dominant taxonomic groups were the Cyanophyceae, Chlorophyceae (with Desmidiaceae dominating), Dinobryon (in the Chrysophyceae), Dinophyceae, and Bacillariophyceae. Similar successional patterns in all 12 ponds occurred, however, the community structure between ponds was not similar at any given time. Although the ponds had statistically similar environmental characteristics, they varied in their community structure indicating that, after one year, they were not mature enough for use as replicate test systems. No structural parameter could be measured with reasonable precision using a three replicate pond scheme recommended by the USEPA. Taxa richness could be measured with a precision of approximately 25% over the year; and was ≤11% during the peak growing months. Taxa densities could usually be measured with a precision of <100% during these months. The in situ oxygen method for measuring primary productivity was found to be to insensitive during early colonization. The heterogeneity of the ponds’ phytoplankton communities indicate that mesocosms will need to be managed to produce replicate experimental units. / Master of Science